Quickie Questions - Phascinating Physics - Space-Time/Relativity

Date Answered

Questioner (age, location)

Question

Answer

September 30, 2009

Bryan (age 28, canada)

Eye sight is the light refecting off an object into our eyes. Iam looking at a clock and clock read 12:00pm. I move away from that clock at the speed of light (assuming I can still read it) Would the clocks time change?

No, the time in the clock, for you, when moving at the speed of light, would stay the same.

September 25, 2009

Sehrish (age 18, Pakistan)

How special theory of relativity explains time dilation

Time dilation happens and the very high speed (near lightspeed) for which the theory was developed. In a simple way it can be expressed as clocks that are moving with respect to an inertial system of observation are measured to be running slower. The mathematical expression to calculate this effect is known as Lorentz transformation.

September 16, 2009

jessica (age 18, nd)

If the speed of light were smaller than it is, would relativistic phenomena be more or less conspicuous than they are now?

Interesting question. Let's see, I would think that they will be more conspicuous, but this could be subjective since our observational methods depend on the speed of light!

August 20, 2009

sam (age 6, )

does time slow down when there is a strong gravitational pull?

Yes, theoreticaly this is what is expected to happen once the "event horizon" of a black hole is reached.

August 20, 2009

Tyler (age 23, California)

Does change in motion affect the mass of an object?

This is no the case for motions at speeds much lower than the speed of light. But near this value (roughly 300 000 m/s), mass is not constant anymore, it becomes a relativistic magnitude.

May 7, 2009

deepak (age 18, india)

if speed of light is not constant then what effect on theory of reletivity

The Theory of Relativity is based on two main assumptions: 1. The speed of light in a vacuum is constant (Principle of Invariant Light Speed), and 2. The physical laws governing motions are not affected, whether these changes of state be referred to the one or the other of two systems in uniform translatory motion relative to each other (Principle of Relativity). If any of these two Principles is shown to be false, the Theory of Relativity would not be valid.

April 17, 2009

akshata (age 14, maharashtra,india)

exactly,what is the wormhole theory? is it which connects two universes together and if yes then theoritically is it that there is existence of other universe if yes then is through time travel?pls answer this question.

This is a very complex issue. A wormhole is any structure connecting two regions or areas otherwise distant or unrelated. They have long been discussed as a possible mode of interstellar travel and even of time travel. This page offers a nice explanation of the theory around wormholes.

October 7, 2008

andrea (age 42, Canada)

Why do people age more slowly in outer space (or even slightly if they live high above sea level like on a mountaintop)?

This is one of the results of the Theory of Relativity. As we approach the speed of light, there a tangible effect of time dilatation (as expressed by the Lorentz Transformation). As a result, time flows "slowly".

June 23, 2008

gary (age , )

Just a "light" attempt to answer your question. Because c is an universal constant, the parameters calculated using it (time, distance, etc) have already considered the relativistic effects. A super-nova exploding NOW at 1 billion light-years, will be observed here in 1 billion years from now.

January 21, 2008

Ian (age 17, ON)

On this website it said that black holes will bend space time, well what does that mean? I can't even visualize that on a 3D scale. If you were to draw that what would it look like if say light were entering the black hole?

According to Albert Einstein's theory of General Relativity spacetime can be visualized as a rubber sheet which gets deformed by any object which has mass or energy. This deformation is called curvature of spacetime. This page offers more infomation and some interesting figures.

July 11, 2007

v (age 13, india)

what is in worm hole?

In physics, a wormhole is a hypothetical topological feature of spacetime that is essentially a 'shortcut' through space and time.

March 7, 2007

Veena (age 13, India)

What is wormhole?

A wormhole is a hypothetical feature of space-time that is essentially a 'shortcut' through space and time. Under the current level of knowledge, they are mostly speculation and theoretical physics (although very used in sci-fi movies!).

November 20, 2000

Karen (age 46, Florida, USA)

What is so special about the date November 19,1999?

We also write this date as 11-19-1999. All of the digits are odd. The next Odd day will be 1-1-3111, which is well over a thousand years away. Days such as 4-13-89 have both even and odd digits, thus, it is neither an Odd nor Even day . There was an Even day on 2-2-2000 - the first one since 8-28-888!

May 11, 1999

Craig (age 38, England)

As the universe is expanding, what is happening to time? Is this also
'growing'. Does that
mean that Time travel to the past is impossible purely because 1 sec of
'new time' would not fit into 1 sec of 'old time'? This may ge a stupid
question but it's stuff like that, that keeps me awake at nights!

Now you have me up all night trying to find the answer! (just kidding) I
guess you can say that time is growing while the Universe is
expanding. If you think about it, every second that goes by adds a little more
to history. However, I don't think we should just assume this makes
time travel
impossible. The idea behind time travel is not to "go faster" than time,
but to somehow skip over
a section. This is the real challenge!

May 10, 1999

Billy (age 56, Texas,USA)

What does red shift mean?

When you are observing an object in space that is moving away from you, the
light
you see is stretched out. This means light is shifted towards the red
end of the spectrum. This is called a red shift. If the o
bject is moving towards you, the light is shifted towards the blue end
and is called a blue shift.

The "Law of Parsimony", or "Law of Economy", is a principle stated by William of Ockham. It says that if two theories explain the facts equally well, then the simpler one is the better one. Ockham used this principle so often and so sharply tha
t it became known as 'Ockham's Razor'.

March 29, 1999

Anna

What is the theory of Einstein's Relativity?

Einstein's Theory of Relativity made predictions about the link between gravity, space and time. Here is a site which can give you the ba
sics.

March 17, 1999

Jamie (age 39, Ontario, Canada)

It is said that we live in a three dimensional world. What are the three dimensions and can you give an example fo each.

We humans actually exist in four dimensions. Three spacial dimensions, which are left-right, forward-backward, and up-down, and one more dimension, time. A point would be one dimensional, a line two dimensional, and a cube three dimensional.
The universe is theorized to have about 10 dimensions.

January 21, 1999

Jeff (age 13, USA)

What is spacetime?

According to the theory of relativity, space and time are not separate things but instead different parts of a four-dimensional continuum. The space-time continuum is the theory that space and time are interconnected. Space is three-dimensional, and
time is one-dimensional, so together they make up the four-dimensional space-time. Space-time is a continuum because, as far as we know, there are no missing points in space or moments in time. It's hard to picture a four-dimensional continuum since our
universe is three dimensional, but you can still know how it works. Think of it as a three-dimensional coordinate system (x,y,z), with one more coordinate for time.

February 19, 1998

Chris (age 8, California, USA)
Kathy and Tony (England)

What is the space-time continuum? Can you explain it?

The space-time continuum is the theory that space and time are interconnected. Space is three-dimensional, and time is one-dimensional, so together they make up the four-dimensional space-time. Space-time is a continuum because, as far as we know, t
here are no missing points in space or moments in time.
Explaining how spacetime works is extremely long and complicated. An excellent book to read, full of examples and illustrations, is Lewis Carroll Epstein's Relativity Visualized.

February 13, 1998

Surjeet (age 15, Michigan, USA)

Is teleportation possible?

Teleportation is the act of making one object disintegrate and a perfect replica appear in another place. Until recently, teleportation was considered to be impossible. However, s
ome scientists have come up with a theory showing how to do it, and others are planning experiments to demonstrate teleportation. However, these experiments involve nothing bigger than single atoms. In terms of teleporting people or large objects, altho
ugh theoretically possible, it will be a very long time before we see it happen.

Who better to describe this than Stephen Hawking! From his book Black Holes and Baby Universes, Hawking writes that the special theory of relativity, "describes how objects move through space and time. It shows that time is not a universal q
uantity which exists on its own, separate from space. Rather, future and past are just directions, like up and down, left and right, forward and back, in something called space-time. You can only go in the future direction in time, but you can go at a b
it of an angle to it. That is why time can pass at different rates." Hawkings goes on to say that the general theory of relativity explains that, "gravity was not just a force that operated in a fixed background of space-time. Instead, gravity was a di
stortion of space-time, caused by the mass and energy in it. Objects like cannonballs and planets try to move on a straight line through space-time, but because space-time is curved, warped, rather than flat, their paths appear to be bent."

January 21, 1998

John (age 16, Arizona, USA)

Has any scientist or cosmologist ever theorized about the existence of any other dimensions? Where can I read more about this?

There has been speculation that there are more dimensions that we normally think of...most scientists will tell you there are 4 dimensions (east-west,north-south,up-down,time). But lately, there have been some physicists who have said there must be
more dimensions than that. Take a look at this web page for a full explanation: dimensions

You might also be interested in:

In the 1920's the famous American astronomer Edwin Hubble made a startling discovery that forever changed our view of the Universe. He found that, no matter which direction he looked into space, distant...more

It depends on which type of motion you are asking about. If you take a birds-eye view from the top of the solar system all the planets orbit around the Sun in a counter-clockwise (or direct) direction....more

Almost everyone has a question or two about living in space. What do astronauts do in space? How do they do everyday things like eat, sleep and go to the bathroom? It's important to note that astronauts...more

There is a really neat internet program called Solar System Live that shows the position of all of the planets and the Sun for any given day. If you go to that page, you'll see an image similar to the...more

The picture of the American Flag (the one put there by the Apollo astronauts) is waving (or straight out) in the wind. How could that be possible if there is no atmosphere on the Moon? Was it some sort...more

I was wondering if there is a new planet? Are there planets (a tenth planet?) after Pluto belonging to our solar system? What are the names of the new planets discovered in the solar system? Are there...more

If that is so, the energy released during the Big Bang must have created many such black holes. Therefore most of the Energy of the Big bang must have disappeared in that form. Then how did the Universe...more